Kick-out switch and buzzer

ABSTRACT

An electric coil is coupled across a pair of normally closed electric contacts which are attached to two electric terminals. The contacts and terminals are supported by pockets in an insulating base member which also supports a bobbin upon which the electric coil is wound. Each terminal is supported within its pocket by a pair of spaced legs having projecting spurs which bite into the margins of the pockets and prevent the terminals from being withdrawn. An armature is pivotally mounted over one end of the coil, and an actuating arm is attached to the armature for opening the contacts in response to a predetermined amount of movement by an object in contact with the actuating arm. This energizes the coil by removing the short circuit around it and causes the armature to buzz until the coil is de-energized.

United States Patent 1151 Schantz et a1.

[ 1 Nov. 12, 1974 KICK-OUT SWITCH AND BUZZER [75] Inventors: Spencer C.Schantz, 16608 W. Rogers Dr., New Berlin, Wis.; William R. Berry,Menomonee Falls, Wis.

[73] Assignee: said Schantz, by said Berry [22] Filed: Oct. 1, 1973 [21]Appl. No.: 402,518

Related US. Application Data [63] Continuation-in-part of Ser. No.306,527, Nov. 15,

[52] US. Cl 335/128, 335/202, 335/281 [51] Int. Cl. HOlh 50/02 [58]Field of Search 335/128, 202, 247, 248, 335/249, 250, 281, 200, 204;339/221 M, 214, 198, 276, 258

[56] References Cited UNITED STATES PATENTS 2,176,564 10 1939 Stumpf335/247 2,942,228 6/1960 Swick 339/258 F 3,355,629 11/1967 Schapira335/128 Primary Examiner-Harold Broomc Attorney, Agent, or Firm-ArthurL. Morsell, Jr.

[57] ABSTRACT An electric coil is coupled across a pair of normallyclosed electric contacts which are attached to two electric terminals.The contacts and terminals are supported by pockets in an insulatingbase member which also supports a bobbin upon which the electric coil iswound. Each terminal is supported within its pocket by a pair of spacedlegs having projecting spurs which bite into the margins of the pocketsand prevent the terminals from being withdrawn. An armature is pivotallymounted over one end of the coil, and an actuating arm is attached tothe armature for opening the contacts in response to a predeterminedamount of movement by an object in contact with the actuating arm. Thisenergizes the coil by removing the short circuit around it and causesthe armature to buzz until the coil is de-energized.

13 Claims, 17 Drawing Figures PATENTELKUVIZW 3.848.205

SHEEI 2 BF 2 2 8 z ,z/O

KICK-OUT SWITCH AND BUZZER CROSS REFERENCE TO RELATED APPLICATIONS Thisapplication is a continuation-in-part of copending application Ser. No.306,527 which was filed on Nov. 15, 1972, for a Kick-Out Switch andBuzzer.

BACKGROUND OF THE INVENTION This invention relates to kick-out switchesand buzzers such as used in connection with washing machines to provideprotection against operation with an unbalanced load in the tub. Duringthe operation of a washing machine, it is possible for the clothes inthe tub to become so bunched together as to seriously unbalance the tuband cause it to wobble excessively as it spins during the spin-dryportion of the operating cycle. Under such unbalanced conditions, it isnecessary to automatically turn the washing machine motor off and tosound an audible alarm which indicates that the washing machine has beenturned off due to an unbalanced condition. In the past, these functionshave been performed by kick-out switches and buzzers.

The prior art kick-out switches and buzzers have utilized a buzzerstructure including a coil which was connected in parallel with a pairof normally closed contacts. The coil and normally closed contacts wereconnected in series with the AC power input to the washing machinemotor. As long as the contacts remained closed, the motor operatednormally and the buzzer was silent due to the short circuit provided bythe normally closed contacts across its coil. When the contacts wereopen, however, this connected the coil in series with the washingmachine motor, thereby turning the motor off, and simultaneouslyenergizing the buzzer. A kick-out actuating arm was connected betweenthe washing machine tub and the switch contacts I to open the contactswhen a predetermined amplitude of wobble was present in the tub. Afterthe kick-out switch and buzzer were actuated, they could be reset totheir initial condition by turning the washing machine I off and thenturning it back on again. This de-energized SUMMARY OF THE INVENTION Inaccordance with this invention, the above-noted drawbacks are overcomeby providing a kick-out switch and buzzer in which the coil, terminals,and contacts are all supported upon a common base member which has abobbin for supporting the coil and two pockets in which the terminalsand contacts are sup ported. The contacts are preferably joined to theterminals by means of contact-supporting arms which extend transverselyfrom the terminals. Slots are formed in the pockets for receiving thecontact-supporting arms. A

pair of spaced legs preferably extends from each of the terminals forengaging the pockets in the base member. A barb is preferably formed onthe outer edge of each leg, and the pockets in the base member arepreferably shaped so that the barbs will bite into the'side margins ofthe pockets when the legs are inserted therein.

A case made of deformable plastic material is preferably fitted over thebase member and is held in place at one end by an enlarged head on apole piece which passes through the center of the bobbin and alsothrough an opening in the top of the case. A ring of deformable plasticmaterial preferably projects upwardly from the top of the case under thehead of the pole piece to compensate for normal variations in the lengthof the pole piece and the height of the case and base member. This ringof deformable plastic material insures that the pole piece and case willfit snugly together with the base member in spite of variations indimensions.

The deformable plastic case and base member are preferably held togetherat their other end by means of a pair of projecting tabs which fit oneon top of the other in an opening of the frame to which the pole pieceis secured. The height of the combined tabs is greater than the heightof the opening and the tabs are force-fitted into the opening. Thisinsures a snug fit in spite of variations in the dimensions of the caseand base member.

An armature is pivotally mounted on the frame for movement toward andaway from the pole piece to produce a buzzing sound when the coil isenergized by an AC voltage. A kick-out actuating arm is preferablyattached to the armature and has a spur portion that extends through thearmature and case and bears against one of the contact-supportingmembers to open the contacts when the actuating arm is moved apredetermined distance toward the pole piece. The kick-out actuating armalso has an outwardly-projecting portion that is shaped and dimensionedto engage a portion of a washing machine tub to be moved thereby. Thekickout actuating arm also preferably has an integral abutment memberthereon for limiting the travel of the armature away from the coil.

One of the contact-supporting arms is spring-biased to hold the contactsin the normally closed position. The spring-biased arm is orienteddiagonally across the plastic case and has a bend therein for increasingthe length of the spring-biased arm and thus reducing the spring rate ofthe arm.

Accordingly, one object of this invention is to provide an improvedkick-out switch and buzzer.

Another object of this invention is to provide a kickout switch andbuzzer having a simplified mechanical structure.

A further object of this invention is to provide a kickout switch andbuzzer which is easier to assemble than those heretofore known in theart.

An additional object of this invention is to provide a kick-out switchand buzzer which is less expensive than those heretofore known in theart.

Another object of this invention is to provide a kickout switch andbuzzer in which the coil, terminals, and contacts are all supported upona common base member.

A further object of this invention is to provide a kickout switch andbuzzer in which each of the terminals and contacts is supported by aspaced pair of barbed tact-supporting springarm which can be used in ofthe arm shown in FIGS. 12-15; and i legs which bite into the sidemargins of a pocket in a base member.

Another object of this invention is to provide a kickout switch andbuzzer in which a ring of deformable plastic material is provided underthe head of the pole piece to compensate for normal variations in thelength of the pole piece and the height of the parts adjacent to thepole piece.

An additional object of this invention is to provide a kick-out switchand buzzer in which the base member and case member are held at one endto the frame by means of a pair of projecting tabs which areforce-fitted into an opening in the frame to compensate for variationsin the dimensions of the case and the base memher.

A further object of this invention is to provide a kickout switch andbuzzer in which an actuating arm having a projecting spur portion actsto open a pair of contacts when moved by a predetermined amount, theactuating arm having a portion which is adapted to engage a portion of awashing machine tub to be moved thereby.

Another object of this invention is to provide a kickout switch andbuzzer in which one of the contactsupporting arms is spring-biased tohold the contacts normally closed and in which the spring-biased contactarm is oriented diagonally across the case and has a bend therein forincreasing the length of the arm and thus reducing the spring rate ofthe arm.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 5 is a perspective view of thebase member of the embodiment shown in FIGS. 1-4;

FIG. 6 is a perspective view of one terminal and contact member of theembodiment shown in FIGS.

FIG." 7 is a top view of the base member shown in I FIG. 5 with theterminal member and contact member shown in FIG. 6 mounted thereon;

FIG. 8 is an enlarged detail view of a ring of deformable plasticmaterial which projects upwardly from the top of the case member shownin FIGS. 1 and 2;

FIGS. 9, l0 and 11 are fragmentary horizonal sectional views with a planview of one of the legs of a terminal member showing progressivepositions in its pocket;

' FIG. 12 is a side view of a second embodiment of the invention in itsnormal or unactuated state, portions of the case being cut away toexpose interior details;

FIG. 13 is a top view of the embodiment shown in FIG. 12, portions ofthe armature and case being cut away to expose interior details; FIG. 14is an enlarged side view of the contactsupporting spring arm shown inFIGS. 12 and 13;

' FIG. 15 is a top view of the contact-supporting spring arm shown inFIG. 14;

FIG-16 is an enlarged side view of an alternate conplace FIG. '17 is atop view of the contact-supporting spring arm shown in FIG. 16.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, oneillustrative embodiment of the invention includes an L-shaped magneticframe 10, a base member 12 which is made of an insulating material, anda case member 14 which is made of a yieldable plastic material. Theframe 10, base member 12, and a case member 14 are held together at oneend by a magnetic pole piece 16 which is staked to the frame 10 at end18 and has an enlarged head 20 at its other end. The enlarged pole piecehead 20 bears against a deformable ring of plastic material 22 whichprojects from the top of case member 14 under the enlarged pole piecehead 20. FIG. 8 shows an enlarged fragmentary detail view of the housing14 and ring 22 separate from the pole piece head 20.

The plastic ring 22, being of yieldable plastic material which isdeformable under pressure, is a particularly important feature of thisinvention whose function is to compensate for variations in thedimensions of the pole piece 16, base member 12, and case member 14. Itwill be understood by those skilled in the art that there will be smallvariations in the dimensions of these members due to normalmanufacturing tolerances and that this variation in dimensions mightpossibly result in a loose fit or an excessively tight fit between themembers when the pole piece 16 is staked at its end 18 onto the frame10. In accordance with this invention, however, the height H of thedeformable plastic ring 22 is selected to exceed the normal variation ofdimensions in the base member 12 and the case member 14 so that theplastic ring 22 will engage the pole piece head 20 when the maximumvariation of dimension occurs in the base member 12, case member 14, andpole piece 16. This insures that the pole piece head 20 will make goodcontact with the ring 22 of the case member 14, to hold the memberssnugly together for all dimensions of the parts involved. When thevariation of dimension is on the long side for the base member 12 andcase member 14, or on the short side for the pole piece 16, thedeformable plastic ring 22 gets crushed almost down onto the top of case14 when the pole piece 16 is staked onto the frame 10 at 18. In theother condition, where the base member 12 and case 14 are on the shortside, or the pole piece 16 is on the long side, the ring of deformableplastic material 22 is only slightly deformed but still holds the case14 snugly against the base member 12 and the, base member 12 snuglyagainst the frame 10.

Another deformable fasteneris provided at the other end of the basemember 12 and case member 14 for holding their other end to the frame 10in spiteof normal variations in dimensions. A tab member 24 projectsfrom the end of base member 12 and a similar tab member 26 projects fromthe end of case member 14. The tab members 24 and 26 fit one on top ofthe other and extend through an opening 28 formed in the frame 10. Theheight of the tab members 24 and 26, taken together, is greater than theheight of the opening 28 by an amount which is equal to or greater thanthe normal variation of height for the tabs 24 and 26. The tab 26 isdeformable and the two tab members 24 and 26 are force-fitted into theopening 28 to insure a snug fit in spite of the normal variations ofdimensions in the tab members 24 and 26 and in the opening 28.

The opening 28 is extended on its lower portion at so as to expedite theinsertion of the tabs 24 and 26 during the assembly process. This is animportant feature of the invention because having the tabs 24 and 26force-fitted into the opening 28 would normally slow down the assemblyprocess and require the application of force in order to assemble theparts. By having the opening 28 extended at the lower end 30, however,the tabs 24 and 26 can be easily inserted into opening 28 at an angle tothe frame when the base member 12 and case member 14 are first placedupon the frame 10, and the force-fit between the tabs 24 and 26 andopening 28 is then effected when the pole piece 16 is staked at end 18onto the frame 10.

Another important feature of the invention is that the base member 12serves as a common support for a coil 32, a pair of contacts 34, and apair of terminals 36. One of the contacts 34 is secured to thecorresponding terminal 36 by means of a contact-supporting arm 38 whichextends transversely from the terminal 36 as shown in FIG. 6, and isbent at right angles to form another contact-supporting arm 40 to whichthe contact 34 is attached. The other contact 34 is attached to aflexible contact-supporting arm 42 which is attached to the rigidcontact-supporting arms 38 and 40 projecting from the side of the otherterminal member 36. The two terminal members 36 and their associatedcontacts 34 are supported in pockets 44 which are formed in the basemember 12 and communicate with opposite edges thereof as shown in FIGS.5 and 7. Slots 45 are formed in the upper surface of pockets 44 to admitthe contactsupporting arms 38 which extend transversely from theterminals 36.

A bobbin 46 having an axial bore 48 through the center thereof isprovided at one end of the base member 12 for supporting the coil 32 andfor allowing the pole piece 16 to pass through the center of the coil32. Slots 50 are formed in'the base member 12 extending between thebobbin 46 and the pockets 44 for carrying wire so that the terminals 36can be connected to the ends of the coil 32.

As best shown in FIGS. 6 and 7, the terminals 36 have spaced parallellegs 52 projecting therefrom which are adapted to fit within the pockets44 to support the terminals 36 and their associated contacts 34. A barb54 is formed on the outer surface of each leg 52 and the margins of thepockets 44 are dimensioned so that the barbs 54 will be able to enterthe pockets easily but will bite into the margins of the pockets 44 whenthe legs 52-are fully inserted therein. As best shown in FIGS. 5 and 7,this is achieved by tapering the margins of the pockets 44 toward theirinner ends as at 43 until the distance between the margins of thepockets are less than the distance between the two barbs. To facilitatethe interaction between the barbs 54 and the side margins of the pockets44, outwardly-tapered surfaces 56 on an integrally molded wedge areprovided within the pockets 44 to engage the inside edges of the legs 52and cause them to move apart slightly as they approach the bottom of thepockets 44 thereby to elastically deform the legs 52, as shown in FIG.10, and force the barbs 54 into the side margins of the pockets 44.Referring to FIGS. 9, l0 and 11, first tip B of a leg 52 encounters thetaper 56, and then, as insertion continues, the beam portion between Aand B of each leg is deformed to a somewhat bowed condition as indicatedby the broken line in FIG. 10. When thus bowed as in FIG. 10, energy isstored in the beam portion between A and B so that the center portion ofthe beam where the barb 54 is located has a tendency to want tostraighten out. Thus when the plastic of FIG. 5 is heated duringsoldering as hereinafter described, it is softened sufficiently that theenergy stored in the bowed beam will cause the beam to straighten out asin FIG. 11, pushing the barb 54 into the side margin of the pocket.

The base member 12 is preferably made of a thermoplastic insulatingmaterial, and when the ends of the coil 32 are soldered to the terminals36, the heat from the soldering operation is conducted down theterminals 36 to the barbs 54 and causes them to bite more deeply intothe side margins of the pockets 44 aided by the energy stored in theelastically deformed legs as above described, and thus helps to seal theterminals 36 in place within the pockets 44 so that they will resistpull out and not become jarred loose by vibration.

Referring to FIGS. 14, a magnetic armature 58 is pivotally attached tothe frame 10 within an opening 60 therein and is normally urged upwardlyaway from the pole piece head 20 by means of an extension spring 62which is attached between the end of the armature 58 and the top marginof the opening 28 in frame member 10. When an AC voltage is appliedacross the winding 32, the alternating magnetic field produced therebyin the frame 10 and in the pole piece 16 will cause the armature 58 toalternately be attracted to the pole piece head 20 and moved away fromthe head 20 by spring 62. This produces a reciprocating action whichmakes an audible buzz. The buzzing action of the buzzer is, however,normally inhibited by the shorting effect of the normally closedcontacts 34.

It is desired to open the contacts 34 to initiate the buzzing action,and also to limit current flow in a washing machine motor connected inseries with the contacts 34, when the tub of the washing machine exceedsa predetermined amplitude of wobble. The above-noted function isperformed by means of an actuating arm 64 which is attached to thearmature 58 by a rivet 66 and which is shaped at one end portion 68 toengage a portion of the washing tub to be moved thereby, and which isshaped at its opposite end 70 to form a spur member which extendsthrough an opening in the armature 58 and through a matching opening inthe top of case member 14 and engages the resilient contact-supportingarm 42 which supports one of the two normally closed contacts 34. Whenthe actuating arm 64 is moved toward the coil 32, the spur portion 70bears against the flexible contact-supporting arm 42 and opens thecontact 34 for a predetermined amount of movement at the other end 68 ofthe actuating arm 64. The contacts 34 are shown in their closedcondition in FIG. 1 and in their fully opened condition in FIG. 2 wherethe actuating arm 64 is moved as far as possible toward the coil 32.

One feature of the actuating arm 64 is that it is shaped to provide thecontact-actuating spur 70 and the tubengaging arm 68 as integral partsof the same unitary member. Another feature is that the rivet 66 ispreferably made of a non-magnetic material, and preferably extends atits lower end 72 below the level of the armature 58 so that when thearmature 58 moves toward the pole piece head 20, the lower end 72 of therivet 66 will hold the armature 58 in a slightly-spaced condition awayfrom the pole piece head 20 to prevent magnetic sticking of the armature58 to the pole piece head 20.

Another feature of the actuating arm 64.is that it has an abutmentmember 74 which interacts with a matching abutment member 76 on casemember 14 for limiting the travel of the armature 58 away from the polepiece head 20 under the urging of the extension spring 62. The abutmentmember 76 is preferably integrally molded with the case member 14, whichis made of plastic material. The fact that abutment members 74 and 76are integrally molded with their respective supporting members 64 and 14is an important feature of this invention because it allows members 64and 14 to perform an additional function at no added cost.

OPERATION OF THE INVENTION In the application of the above-describedembodiment of the invention, the frame of the device is mounted by meansof any suitably prior art fastening means so as to position the extendedportion 68 of the actuating arm 64 in such position that a predeterminedamount of wobble of the washing machine tub will cause the spur member70 of the actuating arm 64 to open the normally closed contacts 34. Theterminals 36 are then electrically coupled in series with the washingmachine motor so that the normal operating current for the washingmachine motor will pass through the contacts 34, which are shortedacross the coil 32, whose ends are coupled to the terminals 36. Thus, inthe normal operation of the washing machine, the current for the washingmachine motor flows through the contacts 34, but the low resistance ofthe contacts 34 does not appreciably alter or impede the flow of currentnor in any way interfere with normal operation of the washing machine aslong as the contacts 34 remain closed.

When the washing machine tub begins to wobble beyond its predeterminedamount, however, this mechanical movement is coupled through the portion68 of the actuating arm 64 and presses the spur portion 70 of theactuating arm 64 sufficiently against the contactsupporting spring 42 tocause the contacts 34 to open. When this occurs, the coil 32 becomescoupled in series with the washing machine motor, which limits thecurrent to'such a low level that the motor ceases operation. The flow ofAC current through the coil 32 sets up an alternating magnetic fieldthrough the pole piece 16, which attracts the armature 58 toward thepole piece head and causes the end 72 of the nonmagnetic rivet 66 tostrike the pole piece head 20. When the alternating magnetic field dropsto zero between cycles, it releases the armature 58 to be moved slightlyaway from the pole piece head 20 before the the contacts 34 remain openand the device acts as a buzzer as long as it is energized by AC voltageapplied across the coil 32. There are two possible ways of resetting thedevice to its original condition: (,1 the actuating arm 64 may bemechanically forced away from the head 20 of pole piece 16 far enoughfor the contacts 34 to close again, which de-energizes the coil 32; or(2) the washing machine switch may be turned off, thereby de-energizingthe coil 32 and allowing the contacts 34 to close as the armature 58moves outwardly away from the pole piece head 20 due tothe urging of theextension spring 62. Either one of these two reset methods can be useddepending upon the particular requirements of the application. Once thedevice has been returned to its original state by either of the tworeset methods, it remains in that state until actuating arm 64 is againmoved by wobble of the washing machine tub to the point where the switchcontacts 34 again become opened.

FIGS. 12 through 15 show a second embodiment of the invention whichdiffers from the above-described embodiment only by the shape of theflexible contactsupporting arm, all other parts being the same asdescribed above. The same reference numerals plus have been used inFIGS. 12 and 13 to designate parts which are identical withpreviously-described parts, e.g., frame member in FIG. 13 is the same asframe member 10 in FIG. 1, base member 112 in FIG. 13 is the same asbase member 12 in FIG. 1, etc.

Referring to FIGS. 12 and 13, the portion of the embodiment whichdiffers from the previously-described embodiment is the flexiblecontactsupporting arm 200 which is attached at one end by a rivet 202 toone of the rigid contact-supporting arms 138 and which is attached atthe other end by a rivet 204 to one of the electrical contacts 134.Flexible contact-supporting arm 200 is made out of electricallyconductive spring material such as phospor bronze or the like and is soshaped as to provide normally closed pressure on the contacts 134, aswill be described hereinafter. A spur projects from actuating arm 164and bears against arm 200 when actuating arm 164 is moved toward case114. When the downward pressure of spur 170 exceeds the upwardly springpressure of arm 200, the contacts 134 will open. The arm 200 is shapedto provide a relatively high pre-tensioning pressure for holding. thecontacts 134 in their normally closed position, and this requires arelatively heavy material for the arm 200. Such relatively heavymaterial has the drawback of having a relatively high spring rate whichrequires a relatively large force to completely open the contacts 134.The spring rate is defined as the increase of spring force per unit ofspring displacement. In accordance with this invention, however, thespring rate of arm 200 is reduced without reducing the pre-tensionedcontact pressure by increasing the effective length of arm 200. This isdone by orienting arm 200 diagonally within case 114 (see FIG. 13) toallow the length of arm 200 to be increased and by providing a U-shapedbend 206 in arm 200 which further increases its effective length. Thisincrease in length reduces the spring rate. Such a reduction in thespring rate could not be achieved by using a thinner material for arm200 because the relatively high initial contact pressure required wouldstress thinner material dangerously near its yield point. Also, arm 200must have a relatively large crosssectional area because the contacts134 carry the motor current for the washing machine or other device withwhich the kick-out switch and buzzer of this invention is employed.

Referring to FIG. 15, the arm 201) has openings 208 and 210 formed inopposite ends thereof for receiving the rivets 202 and 204,respectively. The U-shaped bend 206 is positioned closer to opening 208than to opening 210 to provide a flat area 212 against which the spur170 may bear. As shown in FIG. 14, the portions of arm 200 adjacent tothe bend 206 are bent upwardly at angles C and D to lines which areperpendicular to the sides of bend 206. The angles C and D cause the arm200 to be normally stressed when it is in its rest position (see FIG.12) to provide the above-noted normally closed contact pressure forcontacts 134. The angles C and D are selected in accordance withwellknown prior art techniques to provide the required normally closedcontact pressure. The depth of bend 206 is selected in accordance withthe desired reduction in spring rate within the limitations imposed bythe base member 112; the deeper the bend 206, the greater the increasein effective length of arm 200, and the greater the reduction in thespring rate. For even greater reductions in spring rate, a flexiblecontact-supporting arm 214 (FIGS. 16 and 17) having a serpentine bendwith an upper U-shaped bend 216 and a lower U- shaped bend 218 may beemployed. The serpentine bend provides a somewhat greater increase ineffective length of the contact-supporting arm than a single U- shapedbend of the same depth. Contact-supporting arm 214 has openings 220 and222 formed at opposite ends thereof for receiving rivets 202 and 204,respectively. The portions of arm 214 adjacent to the bends 216 and 218are bent upwardly at angles E and F to lines which are perpendicular tothe sides of bends 216 and 218 to achieve the desired amount of normallyclosed contact pressure.

From the foregoing description it will be clear that this inventionprocies an improved kick-out switch and buzzer which is simpler instructure and less expensive in cost than those heretofore known in theart. And although this invention has been illustrated with reference toseveral specific embodiments, it should be understood that the inventionis not limited to the disclosed embodiments since many modifications canbe made in the disclosed structures without changing their fundamentalprinciples of operation. For example, although only a normally closedpair of electrical contacts has been used in the disclosed embodiment,it is possible that a normally open pair of contacts might also bedesired in other embodiments of the invention and these could be addedwithout in any way altering the operation of the normally closedcontacts. Also, al-

though the spur portion which engages the contactsupporting arm to openthe contacts in the disclosed embodiment is integral with the actuatingarm, it might be desirable in other embodiments of the invention to usea separate spur member for opening the contacts. These and othermodifications of the disclosed structure will be apparent to thoseskilled in the art, and this invention includes all such modificationsas fall within the scope of the following claims.

What I claim is:

1. In an electric switch having a magnetic frame, having a magnetic polepiece mounted on said frame, having an electric coil for said polepiece, having a first electric terminal coupled to one end of said coil,having a second electric terminal coupled to the other end of said coil,having first and second contact-supporting movement toward and away fromthe other to open and close the contacts, and having actuating meansengageable with said flexible contact-supporting arm for moving it toopen and close the contacts, the improvement comprising a base memberattached to said frame and forming a common support for said coil,terminals, contact-supporting arms and contacts, said base member beingmade of an electric insulating material and having an upstanding bobbinprojecting therefrom provided with an axial bore through which said polepiece extends, and said coil being wound around said bobbin, and saidbase member having two pockets each receivinga portion of an electricterminal to support the terminal and the electric contact attachedthereto.

2. An electric switch as defined in claim 1 and further comprising amagnetic armature pivotally mounted for movement toward and away fromthe end of said pole piece, and wherein said actuating means comprisesan actuating arm attached to said armature, one portion of saidactuating arm being shaped and positioned to be engaged by a movablemember to be moved thereby, and another portion of said actuating armbeing shaped and positioned to engage said flexible contactsupportingarm for moving it to open and close the contacts.

3. An electric switch as defined in claim 2 wherein said actuating armis generally Z-shaped.

4. An electric switch as defined in claim 2 wherein said actuating armis connected to said armature by means of a non-magnetic fasteningelement which protrudes from the side of said armature facing the polepiece in such position as to strike the pole piece and hold the armaturespaced slightly from the pole piece to prevent magnetic sticking betweenthe armature and pole piece.

5. In an electric switch having a magnetic frame, having a magnetic polepiece mounted on said frame, having an electric coil for said polepiece, having a first electric terminal coupled to one end of said coil,having a second electric terminal coupled to the other end of said coil,having a base member attached to said frame and forming a common supportfor said coil and terminals, said base member being made of an electricinsulating material and having an upstanding bobbin projecting therefromprovided with an axial bore through which said pole piece extends, saidcoil being wound around said bobbin, the improvement comprising a casefitted over said base member and said coil, said pole piece extendingthrough the top of said case and having an enlarged end adjacent the topof said case, said case being made of a deformable plastic material, andthere being a deformable plastic ring projecting outwardly from the topof said case around said pole piece, whereby the enlarged end of saidpole piece bears snugly against the top of said case in spite ofvariations in the length of said pole piece and the height of said case.

6. An electric switch as defined in claim 5 wherein the height of saiddeformable plastic ring is equal to or greater than the manufacturingtolerance in the length of said pole piece and in the height of saidcase and base member parallel to said pole piece.

7. An electric switch as defined in claim 5 wherein said base member andsaid case each have a tab projecting therefrom, said tabs being alignedone above the other, and wherein there is-an opening in said framealigned with said tabs for receiving the same, and

wherein the height of said combined tabs is equal to or greater than theheight of said opening, and said tabs being force fitted into saidopening.

8. An electric switch as defined in claim 7 wherein said tabs are at theend of said base member which is opposite said pole piece.

9. An electric switch as defined in claim 7 wherein the height of saidcombined tabs exceeds the height of said opening by an amount which isequal to or greater than the combined manufacturing tolerance in theoverall height of said tabs.

10. An electric switch as defined in claim 7 wherein said frame-isL-shaped, said opening being positioned at the bend in said L-shapedframe and extending therefrom toward both ends of said L-shape.

11. An electric switch as defined in claim 2 wherein said actuating armhas an abutment portion projecting from an intermediate portion thereof,and wherein a fixed portion of said switch has a cooperating abutmentportion, said first abutment portion being shaped and positioned to abutagainst said cooperating abutment portion to limit movement of saidactuating arm to inoperative position, said abutment portion beingintegral with said actuating arm.

12. An electric switch as defined in claim 1 l in which the abutmentportion on the switch projects laterally from a casing wall thereof, andin which the abutment portion on the actuating arm is integral with apart of the actuating arm which extends generally parallel to tion ofsaid case.

* l= l= =l=

1. In an electric switch having a magnetic frame, having a magnetic polepiece mounted on said frame, having an electric coil for said polepiece, having a first electric terminal coupled to one end of said coil,having a second electric terminal coupled to the other end of said coil,having first and second contact-supporting arms attached respectively tosaid first and second terminals, having first and second electriccontacts mounted on said contact-supporting arms, one of saidcontact-supporting arms being flexible for relative movement towaRd andaway from the other to open and close the contacts, and having actuatingmeans engageable with said flexible contactsupporting arm for moving itto open and close the contacts, the improvement comprising a base memberattached to said frame and forming a common support for said coil,terminals, contactsupporting arms and contacts, said base member beingmade of an electric insulating material and having an upstanding bobbinprojecting therefrom provided with an axial bore through which said polepiece extends, and said coil being wound around said bobbin, and saidbase member having two pockets each receiving a portion of an electricterminal to support the terminal and the electric contact attachedthereto.
 2. An electric switch as defined in claim 1 and furthercomprising a magnetic armature pivotally mounted for movement toward andaway from the end of said pole piece, and wherein said actuating meanscomprises an actuating arm attached to said armature, one portion ofsaid actuating arm being shaped and positioned to be engaged by amovable member to be moved thereby, and another portion of saidactuating arm being shaped and positioned to engage said flexiblecontact-supporting arm for moving it to open and close the contacts. 3.An electric switch as defined in claim 2 wherein said actuating arm isgenerally Z-shaped.
 4. An electric switch as defined in claim 2 whereinsaid actuating arm is connected to said armature by means of anon-magnetic fastening element which protrudes from the side of saidarmature facing the pole piece in such position as to strike the polepiece and hold the armature spaced slightly from the pole piece toprevent magnetic sticking between the armature and pole piece.
 5. In anelectric switch having a magnetic frame, having a magnetic pole piecemounted on said frame, having an electric coil for said pole piece,having a first electric terminal coupled to one end of said coil, havinga second electric terminal coupled to the other end of said coil, havinga base member attached to said frame and forming a common support forsaid coil and terminals, said base member being made of an electricinsulating material and having an upstanding bobbin projecting therefromprovided with an axial bore through which said pole piece extends, saidcoil being wound around said bobbin, the improvement comprising a casefitted over said base member and said coil, said pole piece extendingthrough the top of said case and having an enlarged end adjacent the topof said case, said case being made of a deformable plastic material, andthere being a deformable plastic ring projecting outwardly from the topof said case around said pole piece, whereby the enlarged end of saidpole piece bears snugly against the top of said case in spite ofvariations in the length of said pole piece and the height of said case.6. An electric switch as defined in claim 5 wherein the height of saiddeformable plastic ring is equal to or greater than the manufacturingtolerance in the length of said pole piece and in the height of saidcase and base member parallel to said pole piece.
 7. An electric switchas defined in claim 5 wherein said base member and said case each have atab projecting therefrom, said tabs being aligned one above the other,and wherein there is an opening in said frame aligned with said tabs forreceiving the same, and wherein the height of said combined tabs isequal to or greater than the height of said opening, and said tabs beingforce fitted into said opening.
 8. An electric switch as defined inclaim 7 wherein said tabs are at the end of said base member which isopposite said pole piece.
 9. An electric switch as defined in claim 7wherein the height of said combined tabs exceeds the height of saidopening by an amount which is equal to or greater than the combinedmanufacturing tolerance in the overall height of said tabs.
 10. Anelectric switch as defined in claim 7 wherein said frame is L-shaped,said opening beIng positioned at the bend in said L-shaped frame andextending therefrom toward both ends of said L-shape.
 11. An electricswitch as defined in claim 2 wherein said actuating arm has an abutmentportion projecting from an intermediate portion thereof, and wherein afixed portion of said switch has a cooperating abutment portion, saidfirst abutment portion being shaped and positioned to abut against saidcooperating abutment portion to limit movement of said actuating arm toinoperative position, said abutment portion being integral with saidactuating arm.
 12. An electric switch as defined in claim 11 in whichthe abutment portion on the switch projects laterally from a casing wallthereof, and in which the abutment portion on the actuating arm isintegral with a part of the actuating arm which extends generallyparallel to said casing wall, there being two other actuating armportions which extend parallel to one another and at substantially rightangles to the portion carrying said abutment member.
 13. An electricswitch as defined in claim 11 and further comprising a case membercovering said base, coil, contact supporting arms, and contacts, theabutment portion of the switch being integral with a side wall portionof said case.